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The following analytic detects a suspicious rundll32.exe process making HTTP connections and performing DNS queries to web domains. It leverages Sysmon EventCode 22 logs to identify these activities. This behavior is significant as it is commonly associated with IcedID malware, where rundll32.exe checks internet connectivity and communicates with C&C servers to download configurations and other components. If confirmed malicious, this activity could allow attackers to establish persistence, download additional payloads, and exfiltrate sensitive data, posing a severe threat to the network.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-14
  • Author: Teoderick Contreras, Splunk
  • ID: f1483f5e-ee29-11eb-9d23-acde48001122




ID Technique Tactic
T1218 System Binary Proxy Execution Defense Evasion
T1218.011 Rundll32 Defense Evasion
Kill Chain Phase
  • Exploitation
  • DE.CM
  • CIS 10
`sysmon` EventCode=22 process_name="rundll32.exe" 
| stats count min(_time) as firstTime max(_time) as lastTime values(query) as query values(answer) as answer values(QueryResults) as query_results values(QueryStatus) as query_status by process_name process_guid Computer 
| rename Computer as dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `rundll32_dnsquery_filter`


The SPL above uses the following Macros:

:information_source: rundll32_dnsquery_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • Image
  • QueryName
  • QueryStatus
  • ProcessId
  • dest

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name and eventcode = 22 dnsquery executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA. Tune and filter known instances where renamed rundll32.exe may be used.

Known False Positives


Associated Analytic Story


Risk Score Impact Confidence Message
56.0 70 80 rundll32 process $process_name$ made a DNS query for $query$ from host $dest$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.


Test Dataset

Replay any dataset to Splunk Enterprise by using our tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 3